1. Field of the Invention
The invention relates to a bullet-proof window for installation in the wall of a banking building to protect a bank teller carrying out a banking operation inside the window with visual communication with a customer outside the window. More particularly, the invention relates to an inexpensive metal frame composed of formed sheet metal sill, head and side members, in which bullet-proof glass may be installed from the outside of the window but clamped from the inside of the window to provide a sealed joint between the glass and frame that is weather-proof and need not be caulked, and is secure against attack by an intruder attempting to remove the bullet-proof glass from outside the building.
2. Description of the Prior Art
Bank windows in which bullet-proof glass may be installed in a modular manner for large banking buildings to accommodate various sizes of window-receiving openings and building walls of various thicknesses are known, in which bullet-proof glass may be installed from the exterior of the window and clamped from the interior thereof; for example, as shown in my application Ser. No. 528,004, filed Nov. 29, 1974, now U.S. Pat. No. 3,994,243.
Such prior bullet-proof glass window constructions, however, are too expensive to compete with bullet-proof glass windows installed by building contractors erecting small banking facility buildings at shopping centers and other locations remote from a main banking facility. In many instances, the local building contractors obtain bullet-proof glass from any available source, and construct a glass and window frame which is built into a building wall as the wall is being erected. Such frames are made of angle iron members, extruded metal members, or wooden members. Caulking is used to seal the bullet-proof glass in such frames. If it is necessary to replace the glass, the entire frame must be removed and rebuilt.
There are many known prior art wooden or metal frames for simple glass windows in residential buildings, business buildings, automobiles, and the like. The glass is clamped in such window frames by retaining means whose clamping screws or the like are accessible only at the same side of the frame at which the glass is entered into the frame, either at the inside or the outside of the wall in which the window frame is located. Examples of such prior art window frames are present in U.S. Pat. Nos. 2,386,151, 2,791,007, 2,995,221, 2,996,767, and 3,768,220.
It is undesirable to use a frame construction for bullet-proof glass in the wall of a banking building in which the clamping screws for the glass retaining means are accessible at the same side of the frame at which the glass is entered into the frame. If the retainer clamping means and glass entry are both located at the outside of the window, glass removal is possible by an intruder at a remote location of the building during the night season for entering the building.
If glass entry and clamping means are both located at the inside of the window, then if necessary to replace the bullet-proof glass, because of damage thereto, it is necessary to disturb banking operations and interrupt teller services in banking areas in the building at and leading to the window location, to transport the bullet-proof glass through such banking areas and to install the glass in the window frame, which is not desirable.
Accordingly, there is an existing need for a bullet-proof glass window construction for a bank building wall which is simple and inexpensive to fabricate and install, in which the bullet-proof glass may be readily replaced at the outside of the wall but clamped in retained position with clamping means only accessible at the inside of the wall, and in which a sealed weather-proof joint around the perimeter of the bullet-proof glass may be provided by the glass retainer clamping means without requiring caulking.